If you edit a content in a backend and the template in question has a cache-block, the preview won't be updated.
- Change ezpublish.yml and set your frontend siteaccess to have legacy_mode: true
- Edit your design Full\Article template and add a cache block around the body attribute
- Clear the caches
- Edit an existent article, and change the body.
- Go back to edit
- Edit that article again, and change the body again.
You won't be able to see content changes this time